CALL SEQUENCE...
       meriavg  GGIN MMOUT OUTPUT \ 
                [ -lon VAL1 ] [ -kind VAL2 VAL3 VAL4 VAL5 VAL6 ]
 
 
      DESCRIPTION...
       meriavg  - COMPUTES MULTI-LEVEL MERIDIONAL AVERAGE OF A SET OF GRIDS 
  
 
      AUTHOR  - B.Dugas, JAN/06.
      LAST REVISION: $Header: /home/cvs/RMNLIB/utils/rdiag/lspgm/meriavg.ptn,v 4.6 2014/09/25 20:20:51 dugas Exp $
 
  
      PURPOSE - COMPUTES A VECTOR OF MERIDIONAL MEANS FOR EACH GRID
                AND SAVES THEM ON FILE MMOUT. 
 
      NOTES:  1) EACH MMOUT RECORD IS A LONGITUDINAL VECTOR OF AVERAGES 
                 RUNNING EAST TO WEST. MAXIMUM NUMBER OF LEVELS IS 999.
              2) WHEN DEALING WITH VECTORS COMPONENTS ON A ROTATED TYPE
                 'Z' FRAMEWORK, ggvecz SHOULD HAVE ALLREADY BEEN APPLIED
                 TO THESE VECTOR COMPONENTS, OTHERWISE THE RESULT WILL
                 BE IN ERROR.
 
  
      INPUT FILE ... 
       GGIN  = (REAL OR COMPLEX) GRIDS TO BE MERIDIONALY AVERAGED. 
 
      OUTPUT FILE ... 
       MMOUT = MERIDIONAL AVERAGES OF EACH GRID IN GGIN. 
 
 
      (OPTIONAL) PARAMETRE (ONLY WITH GEM Z-TYPE INPUT GRIDS) ...
 
       LON  = NUMBER OF LONGITUDES IN THE OUTPUT MERIDIONAL CROSS-SECTIONS.
              DEFAULTS TO THE MAXIMUM OF THE TWO HORIZONTAL DIMENSIONS
              OF THE INPUT FIELDS.
 
      (OPTIONAL) PARAMETRES (ONLY WITH CCC-TYPE FILES) ...
       KIND    = FIRST VALUE DENOTES GRTYP (THE GRID TYPE) (def=G). THE
                 ONLY SUPPORTED VALUES ARE A,B,G,L RPN/CMC GRIDS. Z GRIDS
                 ARE NOT SUPPORTED WITH CCC FILES.
               = THE FOUR NEXT VALUES ARE THE DECODED VERSION OF THE IGi,
                 THE RPN/CMC INTERNAL GRID DESCRIPTORS (defs=0.0).
 
       PLEASE REFER TO THE RPN STANDARD FILE ONLINE DOCUMENTATION
       FOR DETAILS CONCERNING THE USE OF THESE FIVE ARGUMENTS.
 
 
      EXIT CONDITIONS...
        0 NO PROBLEMS
        1 PROBLEMS READING GGIN
        2 FOUND UNSUPPORTED ARRAY TYPE
        3 PREMATURE EOF ON FILE GGIN
        4 MORE THAN ONE SIZE IN INPUT FILE
        5 ERROR READING INPUT PARAMETRE